When pressing shutdown/reboot, Kate will abort system shutdown if there are modified/new files. It should try to cope with the shutdown when feasible.

The way Notepad++ does it is very useful: it keeps some temporaries and at start-up it reloads them all:
- modified appear as unsaved
- never saved appear as new.

This partly breaks KDE session saving, since many programs are already closed by the time I finish with Kate, and restoration will not restore everything.

Reproducible: Always

Steps to Reproduce:
1. Create a new file and type something in in
2. Press Alt+F1 and choose "reboot"
3. Notice that Kate will abord the shutdown process.